Method and system for determining horizontal distance between transmitting point and receiving point

The present invention discloses a method and system for determining a horizontal distance between a transmitting point and a receiving point. The method obtains a depth value of the transmitting point and a depth value of the receiving point. An area of a sound velocity profile according to the depth value of the transmitting point and the depth value of the receiving point is then determined. A sound velocity gradient according to the area of the sound velocity profile is also determined. The horizontal distance between the transmitting point and the receiving point according to the sound velocity gradient is then determined by calculations. The present invention eliminates the need to calculate a grazing angle of an eigen sound ray(wave) connecting the transmitting point and the receiving point, by directly converting a propagation time into the horizontal distance, thereby quickly and efficiently calculating the horizontal distance between the transmitting point and the receiving point.